U.S. patent application number 12/811289 was filed with the patent office on 2011-01-27 for trimmer comb, hair trimmer comprising a trimmer comb and method of manufacturing a trimmer comb.
Invention is credited to Juergen Behrendt, Klaus-Dieter Geiser, Andreas Larscheid.
Application Number | 20110016729 12/811289 |
Document ID | / |
Family ID | 39502900 |
Filed Date | 2011-01-27 |
United States Patent
Application |
20110016729 |
Kind Code |
A1 |
Geiser; Klaus-Dieter ; et
al. |
January 27, 2011 |
TRIMMER COMB, HAIR TRIMMER COMPRISING A TRIMMER COMB AND METHOD OF
MANUFACTURING A TRIMMER COMB
Abstract
The invention is concerned with a trimmer comb (1) that
comprises a base sheet (10) that has a toothed front side, the
toothed front side comprising a side-by-side arrangement of guard
teeth (11) and narrow teeth (12). The length (E2) of the narrow
teeth (12) measured in axial direction of the trimmer comb teeth
(x) is smaller than the length (E1) of the guard teeth (11) and
further the guard teeth (11) have widened tips (15, 11d, 11d').
These two different trimmer comb teeth geometries serve to press
down skin and to avoid injuries by hooking of trimmer comb teeth
into skin pores or hair channels, while a high cutting efficiency
is ensured because the smaller narrow teeth allow for a reduced
average spacing distance between the trimmer teeth. The invention
is also concerned with a hair trimmer comprising such a trimmer
comb and a hair removal device comprising such a hair trimmer.
Inventors: |
Geiser; Klaus-Dieter;
(Neu-Anspach, DE) ; Behrendt; Juergen; (Brechen,
DE) ; Larscheid; Andreas; (Sulzbach, DE) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY;Global Legal Department - IP
Sycamore Building - 4th Floor, 299 East Sixth Street
CINCINNATI
OH
45202
US
|
Family ID: |
39502900 |
Appl. No.: |
12/811289 |
Filed: |
January 27, 2009 |
PCT Filed: |
January 27, 2009 |
PCT NO: |
PCT/EP09/00507 |
371 Date: |
September 30, 2010 |
Current U.S.
Class: |
30/233.5 |
Current CPC
Class: |
B23K 26/0006 20130101;
B23K 2103/50 20180801; B23K 2103/52 20180801; B23K 2103/04
20180801; B26B 19/06 20130101; B26B 19/3846 20130101; B23K 26/354
20151001 |
Class at
Publication: |
30/233.5 |
International
Class: |
B26B 13/00 20060101
B26B013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 2008 |
EP |
08001619.9 |
Claims
1. Trimmer comb (1) comprising a base sheet (10) that has a toothed
front side, the toothed front side comprising a side-by-side
arrangement of guard teeth (11) and narrow teeth (12), wherein the
length (E2) of the narrow teeth (12) measured in axial direction of
the trimmer comb teeth (x) is less than the length (E1) of the
guard teeth (11), characterized in that the guard teeth (11) have
tips (15, 11d, 11d') that are widened in the longitudinal extension
direction (y).
2. Trimmer comb according to claim 1, wherein the base spacing
(D2') of the narrow teeth (12) is less than the base spacing (D2)
of the guard teeth (11).
3. Trimmer comb according to claim 1 or claim 2, wherein the tips
(15, 11d, 11d') of the guard teeth (11) are about as wide or wider
in the longitudinal extension direction (y) of the trimmer comb
than the average spacing distance (D.sub.avg) between the guard
teeth (11) and the narrow teeth (12).
4. Trimmer comb according to any one of claims 1 to 3, wherein
between two guard teeth (11) at least a narrow tooth (12) is
arranged, in particular wherein the guard teeth (11) and the narrow
teeth (12) are arranged in an alternating manner.
5. Trimmer comb according to any one of claims 1 to 4, wherein the
thickness (d) of the base sheet (10) at the toothed front side is
equal to or smaller than about 0.4 mm, in particular the thickness
(d) of the base sheet (10) is equal to or smaller than 0.3 mm.
6. Trimmer comb according to any one of claims 1 to 5, wherein the
centre spacing distance (D4) between the centre of a narrow tooth
(12) and the centre of an adjoining tooth gap (13) is less than the
centre width (W.sub.c) of a guard tooth (11) measured at half the
axial extension of the narrow teeth (12) between base sheet (10)
and tip, in particular where the centre spacing distance (D4)
between the centre of a narrow tooth (12) and the centre of an
adjoining tooth gap is about the centre width (w.sub.c) of a narrow
tooth (12).
7. Trimmer comb according to any one of claims 1 to 6, wherein the
centre width (w.sub.c) of a narrow tooth (12) measured at half the
axial extension of the narrow teeth (12) between base sheet (10)
and tip is at least 20% smaller than the centre width (W.sub.c) of
a guard tooth (11), in particular wherein the centre width
(w.sub.c) of a narrow tooth (12) is at least 30% smaller than the
centre width (W.sub.c) of a guard tooth (11) and specifically
wherein the centre width (w.sub.c) of a narrow tooth (12) is at
least 40% smaller than the centre width (W.sub.c) of a guard tooth
(11).
8. Trimmer comb according to any one of claims 1 to 7, wherein at
least a guard tooth (11) has a thickened tip (11d, 11d') that is
thickened in a height direction (z).
9. Trimmer comb according to the previous claim, wherein the
thickened tip (11d, 11d') is extending to the skin side of the
guard tooth (11).
10. Trimmer comb according to claim 9, wherein the thickened tip
(11d, 11d') comprises a thickened tip portion (11b) that is a
spherical structure having a diameter (D) larger than the thickness
(d) of the base sheet (10).
11. Trimmer comb according to the claim 10, wherein the spherical
structure has a diameter (D) at least 50% larger than the thickness
(d) of the base sheet (10), in particular wherein the diameter (D)
of the spherical structure (11b) is at least twice as large as the
thickness (d) of the base sheet (10).
12. Hair trimmer (200) comprising at least a trimmer comb (1)
according to one of the claims 1 to 11, wherein the trimmer comb
(1) cooperates with a trimmer blade (8) to cut hairs in a use
operation.
13. Hair trimmer according to claim 12, wherein the trimmer blade
(8) has a toothed front side that is--in an operating state of the
hair trimmer--relatively moved with respect to the toothed front
side of the trimmer comb (1).
14. Hair removal device (300) comprising at least a hair trimmer
(200) according to claim 12 or claim 13.
Description
[0001] The invention is concerned with a trimmer comb, a hair
trimmer device comprising a trimmer comb, a hair removal device
comprising a hair trimmer device, and a method of manufacturing a
trimmer comb.
[0002] Japanese patent application JP 02-052688 discloses a trimmer
comb having a toothed front side, where each trimmer comb tooth has
a circular tip area in the trimmer comb plane. The diameter of the
circular tip area is larger than the width of the tooth at the
position where the circular tip is attached to the tooth. When
viewed from the side, the trimmer teeth have an approximately
hemispherical thickening that forms the tip of the trimmer teeth.
The thickened tips induce a pleasant skin contact sensation.
[0003] International patent application WO 2007/069177 A2 also
discloses thickened tips of trimmer comb teeth, specifically
focusing on the problem of hooking of trimmer comb teeth into skin
pores or hair channels, causing painful injuries.
[0004] Japanese laid open patent document JP 54-130272 A2 discloses
a trimmer comb that has two different kinds of trimmer teeth, where
one kind of teeth is wider in the longitudinal extension direction
or thicker in the height direction or longer in the axial extension
direction than the other kind of teeth. The two kinds of teeth are
arranged in an alternating manner such that between two teeth of
the wider or thicker or longer kind two teeth of the other kind are
arranged.
[0005] It is known that hooking of trimmer teeth into skin pores
can be avoided by thickened trimmer tooth tips and that cutting of
skin that penetrates through tooth gaps can be avoided by narrow
tooth gaps. But it is a disadvantage of the known designs that wide
trimmer tooth tips avoiding injuries by hooking require a certain
tooth spacing that is given by the required tip width. This
relatively large tooth spacing leads to a reduced cutting
efficiency of the known trimmer combs.
[0006] It is hence an object of the present invention to provide a
trimmer comb that avoids injuries while a high cutting efficiency
is ensured.
[0007] The object of the invention is solved by a trimmer comb
according to claim 1. Additional embodiments are given by the
dependent claims.
[0008] The proposed trimmer comb comprises a base sheet that has a
toothed front side (as is generally known in the art). The toothed
front side comprises a side-by-side arrangement of guard teeth and
narrow teeth. The guard teeth have tips that are widened in the
longitudinal extension direction of the trimmer comb (which is the
lateral extension direction of the guard teeth, respectively),
which means that the guard tooth has a certain first width and the
width of the tips increases from this first width to a second
width. The presence of the widened tips of the guard teeth provides
a reduction of hooking injuries when compared with a trimmer comb
without such widened tips. The narrow teeth are not as long as the
guard teeth (the length of a tooth is measured in axial direction
from the base plate to the tip). Hence, the widened tips of the
guard teeth may specifically extend into the gap between the tip
regions of the guard teeth into which the narrow teeth do not
extend. Hence, a reduction of hooking injuries can be realised
without the need to essentially reduce the average spacing distance
between the teeth of the trimmer comb, which as a result maintains
a high cutting efficiency. It is to be understood that a tip of a
guard tooth is a three-dimensional structure and that the widened
tip could also be realised by having e.g. a spherical structure
placed on top of the guard tooth where the maximal width of the
guard tooth tips is realised at a different height position than
the height position of the narrow tooth.
[0009] In an embodiment of the proposed trimmer comb, the base
spacing of the narrow tooth is smaller than the base spacing of the
guard teeth (which essentially means that the overall width of the
narrow teeth is smaller than the general width of the guard teeth).
This also allows for a reduced average spacing distance between
guard teeth and narrow teeth and hence a good cutting
efficiency.
[0010] In an embodiment of the proposed trimmer comb, a narrow
tooth is arranged between two guard teeth. In this alternating
arrangement, the benefits of the different geometries of the guard
teeth and the narrow teeth could be used by adapting the reduced
geometry of the narrow teeth to the geometry of the guard teeth and
the required width of the tooth gaps.
[0011] In another embodiment of the proposed trimmer comb, the
thickness of the base sheet is equal to or smaller than 0.4 mm, in
particular the thickness of the base sheet is equal to or smaller
than 0.3 mm. As the proposed reduced geometry of the narrow teeth
allows reducing the average spacing distance, the tooth gaps could
become smaller and as a result, the skin can not easily penetrate
through the tooth gaps and gets cut, which allows using a thin base
sheet as thin as about 0.3 mm.
[0012] In an embodiment of the proposed trimmer comb, the
centre-to-centre spacing distance between a narrow tooth and an
adjoining tooth gap is smaller than the centre width of a guard
tooth, in particular, the centre-to-centre spacing distance of a
narrow tooth and an adjoining tooth gap is about the centre width
of a narrow tooth. Here, the centre width of a narrow tooth or a
guard tooth or of a tooth gap is measured at half the axial
extension length of the narrow teeth.
[0013] For the proposed trimmer comb, the tips of the guard teeth
define a skin contact edge (or: the tips of the guard teeth define
an enveloping edge of the trimmer comb front) and the narrow teeth
do not extend until the skin contact edge. This specific design
further ensures that hooking of the smaller tips of the narrow
teeth is effectively avoided (even though the wide tips of the
guard teeth press down the skin, the skin may raise--specifically
in regions where the skin is flexible--and tips of the narrow teeth
extending up to the skin contact edge may still hook into skin
pores or hair channels). As the narrow teeth do not extend up to
the skin contact edge, the tips of the guard teeth can be designed
even wider, as the tips of the narrow teeth are in a retracted
position. This enhances the ability of the trimmer comb to press
down skin and the possibility for injuries is suppressed while a
low average spacing distance between the trimmer comb teeth is
preserved.
[0014] In a refinement of the previous embodiment, the tips of the
guard teeth are about as wide or even wider (in the longitudinal
extension direction of the trimmer comb) than the average spacing
distance between the guard teeth and the narrow teeth.
[0015] In an embodiment of the proposed trimmer comb, the narrow
teeth have a centre width that is 20% smaller than the centre width
of the guard teeth, in particular this value is 30% and
specifically this value is 40%.
[0016] In a further embodiment of the proposed trimmer comb, at
least a guard tooth has a tip that is thickened in a height
direction (the height direction being perpendicular to the trimmer
comb plane spanned by the toothed front side of the trimmer comb).
By having a wide tip of the guard tooth that is also thickened in
the height direction, hooking is even better suppressed and a
thickened tip (specifically, if it is a smooth spherical tip
portion) also may generate a skin contact sensation more pleasant
than the skin contact sensation of a non-thickened (flat) thickened
(flat) tooth having only base sheet thickness. Obviously, thickened
in the height direction means that the thickened tip portion has a
maximal thickness that is larger than the thickness of the base
sheet.
[0017] In a further refinement of the previous embodiment, the
thickened tip extends to the skin side of the guard tooth, where
the skin side of the trimmer comb is intended to contact the skin
in a use operation of the mounted trimmer comb. In a refinement of
this embodiment, the thickened tip comprises a thickened tip
portion that is a spherical structure having a diameter larger than
the thickness of the base sheet, in particular where the diameter
of the spherical structure is at least twice as large as the
thickness of the base sheet.
[0018] The invention also is concerned with a hair trimmer device
in which a proposed trimmer comb is utilized and the invention
further is concerned with a hair removal device in which such a
hair trimmer device is a (integral) part.
[0019] The invention will be further described in detail by
explanation of exemplary embodiments and by reference to figures.
In the figures
[0020] FIG. 1 shows an exemplary detail of a trimmer comb having
guard teeth and narrow teeth,
[0021] FIG. 2 shows a schematic drawing of an exemplary embodiment
of a toothed front side of a trimmer comb as proposed in a top view
onto the comb plane,
[0022] FIG. 3 shows a schematic drawing of a frontal view onto a
toothed front side of a trimmer comb as proposed and a trimmer
blade, where at the front of the trimmer comb various realization
possibilities of guard teeth are indicated,
[0023] FIG. 4 shows a perspective view onto an exemplary
intermediate trimmer comb during manufacturing, where a detail of
the toothed front side is magnified,
[0024] FIG. 5 shows a top view onto the exemplary intermediate
trimmer comb as shown in FIG. 4,
[0025] FIG. 6 shows a top view onto a detail of an intermediate
trimmer comb,
[0026] FIG. 7 shows a frontal view onto the toothed front side of
the intermediate trimmer comb as shown in FIG. 4,
[0027] FIG. 8 shows a side view onto the intermediate trimmer comb
as shown in FIG. 4 and indicates the application of energy onto a
bent-over portion of a guard tooth,
[0028] FIG. 9 shows a side view onto a trimmer comb in its final
stage after energy had been applied to the bent-over portion so
that a molten tip portion resulted,
[0029] FIG. 10 shows a perspective view onto a trimmer comb in its
final stage,
[0030] FIG. 11 shows a magnification of a detail of the toothed
front side of the trimmer comb as shown in FIG. 10, and
[0031] FIG. 12 shows an exemplary hair removal device in which a
trimmer comb is used as a part of a hair trimmer of the hair
removal device.
[0032] A hair trimmer device for trimming hair usually comprises a
trimmer comb and a trimmer blade, both having toothed front sides
that have teeth that are arranged in a side-by-side manner and that
extend in a comb plane and a blade plane, respectively. In a
mounted state, the trimmer comb and the trimmer blade are arranged
on top of each other so that the toothed front sides are superposed
in a tight-fit manner, usually under pre-stress, e.g. applied by a
spring. In an operation state, the toothed front sides of the
trimmer comb and the trimmer blade are moved relatively to each
other so that hairs that feed into the teeth gaps will be sheared
off or cut off. Such a hair trimmer device, e.g. a beard trimmer, a
long hair trimmer, a precision trimmer for facial hairs etc., could
be a stand-alone device or the hair trimmer device could be a
(integral) part of a different device, e.g. a hair removal device
comprising a hair removal unit, such as an electric shaver or a wet
shaver or an epilator head, and a hair trimmer device.
[0033] In the following, the description focuses on various
embodiments of trimmer combs, but it is to be understood that the
subject matter of the description shall encompass also hair trimmer
devices and hair removal devices in which such a trimmer comb is
employed.
[0034] FIG. 1 shows a detail of a trimmer comb as is essentially
known from JP 54-130272 A2 (the shown detail corresponds to the
detail A as indicated in FIG. 3 for an exemplary embodiment of a
trimmer comb as proposed) that extends in a trimmer plane, where a
Cartesian coordinate system spanning the trimmer comb plane is
indicated, which coordinate system has an axis x that extends in an
axial (tooth) extension direction and an axis y that extends in a
longitudinal extension direction of the trimmer comb. The trimmer
comb comprises a base sheet 10. The base sheet 10 has a toothed
front side that has a first plurality of teeth 11 ("guard teeth")
and a second plurality of teeth 12 ("narrow teeth") that have two
different tooth geometries, in particular the guard teeth 11 have a
wider width than the narrow teeth 12 (the tooth width is defined in
the longitudinal extension direction of the trimmer comb, viz. the
y direction as indicated by the Cartesian coordinates) and usually
shall mean the centre width of the tooth--it is referred to W.sub.c
and w.sub.c in FIG. 4, where the centre width shall be measured at
half the axial extension of the narrow teeth 12), where the guard
teeth 11 and the narrow teeth 12 are arranged side-by-side in an
alternating manner. Each guard tooth 11 has a tip 15 that is wider
than a tip 15' of a narrow tooth 12.
[0035] In FIG. 2 a schematic cut-out detail of an exemplary
embodiment of a toothed front side of a trimmer comb as proposed is
shown. Even though it is shown in FIG. 2 that a single narrow tooth
12 is arranged between two guard teeth 11, any other periodic or
non-periodic arrangement of guard teeth 11 and narrow teeth 12 of
the proposed trimmer comb should be covered by the subject matter
of the description. The toothed front side of the base sheet 10 has
guard teeth 11 and narrow teeth 12 that are arranged in an
alternating side-by-side manner. In this embodiment, the guard
teeth 11 have a mushroom-like geometry, where the tips 15 of the
guard teeth 12 are widened similarly to the head of a mushroom. In
the shown embodiment, the guard teeth 11 first taper slightly
(which means that their width is slightly reduced with increasing
axial extension length) and then the guard teeth tips widen in
their width so that a mushroom-like structure results. The narrow
teeth 12 have a reduced geometry when compared to the guard teeth
11. They slightly taper from the base of the narrow teeth 12 at the
base sheet 10 to the tips 15' of the narrow teeth 12 and are
generally less wide than the guard teeth 11. The guard teeth 11
extend in the axial extension direction x until a line L2 that
represents a skin contact edge. The narrow teeth 12 extend in the
axial extension direction x only until a line L1. The widened
(mushroom-like) tips 15 of the guard teeth 11 are here formed
between line L1 and line L2. As the narrow teeth 12 extend only
until line L1, the tips 15 of the guard teeth 11 can be made rather
wide, as the area between the guard tooth tips 15 is not needed by
the tips 15' of the narrow teeth 12. In this way, wide guard tooth
tips 15 can be formed; those wide guard tooth tips 15 serve to
press down the skin and also, in case the width of the guard tooth
tips 15 is chosen wide enough, they do not hook into skin pores or
hair channels. Still, a gap 16 sufficiently wide to feed hairs into
the teeth gaps 13, where the teeth gaps 13, where the hairs will
ultimately be cut in a use operation, remains. As the stems of the
mushroom-like formed guard teeth 11 can be made less wide than the
guard tooth tips 15, a low average spacing distance D.sub.avg
(measured in y direction) between guard teeth 11 and narrow teeth
12 can be achieved, so that a high cutting efficiency of the
proposed trimmer comb is obtained. The individual base spacing of a
guard tooth 11, measured from the base centre of a tooth gap 13 on
one side of a guard tooth 11 to the base centre of a tooth gap 13
on the other side of the same guard tooth 11, is D2 and the base
spacing of a narrow tooth 12 measured between a base centre of a
tooth gap 13 on one side of a narrow tooth 12 to the base centre of
a tooth gap 13 on the other side of the same narrow tooth 12, is
D2', so that D1=D2+D2'=2D.sub.avg. It is a specific feature of the
discussed embodiments that D2>D2', as the smaller base spacing
D2' of the narrow teeth 12 leads to a good cutting efficiency,
while the larger base spacing D2 allows to have wide tips of the
guard teeth 11 due to the enhanced stability of the wider guard
teeth 11. As the narrow teeth 12 are additionally retracted (do not
extend up to the skin contact edge L2, which means that the narrow
teeth 12 are shorter in axial extension length x than the guard
teeth 11), the tips 15 could be made even wider than would be
allowed for equally long guard teeth 11 and narrow teeth 12, as the
retracted narrow teeth 12 leave enough space for hairs to become
fed into the tooth gaps 13 even with those very wide tips 15 as
shown. Hence, in the discussed embodiment, the width W.sub.g of the
tips 15 of the guard teeth 11 (the width W.sub.g is defined as the
maximum extension in y direction of the widened tip 15) is larger
than the average spacing distance D.sub.avg between the trimmer
comb teeth. Here, having an alternating arrangement of guard teeth
11 and narrow teeth 12, the average spacing distance D.sub.avg is
half the spacing distance D1 between pairs of a guard tooth 11 and
a narrow tooth 12. In a non-periodic arrangement of guard teeth 11
and narrow teeth 12, the overall width of the toothed front side of
the trimmer comb in y direction divided by the number of teeth
defines the average spacing distance D.sub.avg. Generally, the
guard teeth 11 cover an area A1 (measured from their basis at the
base sheet 10) in the trimmer comb plane that is larger than the
area A2 of the narrow teeth 12. For the shown specific embodiment,
the width W.sub.g of the tips 15 of the guard teeth 11 could be
about 0.7 mm while an average spacing distance between tooth gaps
13 of about 0.45 mm is achieved. The width of the tip 15' of a
narrow tooth 12 would be measured at a line where the tapered part
of the narrow tooth 12 merges with the rounded tip portion. If the
tip 15' of a narrow tooth 12 would be flat at the front, the width
of the flat front would be taken as the width of the tip 15' of the
narrow tooth 12.
[0036] The guard teeth 11 with their wide tips 15 serve to press
down the skin, so that cutting the skin, especially in body areas
where flexible and thin skin is present (e.g. in the armpit and the
intimate area), is efficiently suppressed. In a specific
embodiment, the tips 15 of the guard teeth 11 are chosen so wide
that they would not hook into a hair follicle opening at the skin
surface (e.g. the width of the tips 15 could be 0.6 mm-1.0 mm). As
the hair follicles openings at the skin surface (also named hair
channels), specifically in the intimate area, are rather large in
diameter (and further because of the funnel-like structure of the
hair channels at the skin surface and because of the high
flexibility of the skin in the intimate area), one would choose a
rather large width W.sub.g of the tips 15 of the guard teeth 11.
Without prejudice, the tips 15 of the guard teeth 11 (and also the
tips 15' of the narrow teeth 12) could be rounded for a gentle skin
feeling or the tips 15 of the guard teeth 11 could be thickened in
the height direction as is known in the art, e.g. the teeth of the
trimmer comb utilized in the Braun Lady Shaver have laser-molten
and thickened tips since 1985 to improve the skin contact sensation
of the trimmer comb (FIG. 3 shows a schematic depiction of such a
thickened tip 11d'). It is noted that the tooth gaps 13 between the
guard teeth 11 and the narrow teeth 12 are chosen rather narrow (in
an exemplary embodiment, the centre width of the tooth gaps 13 has
about the same size as the centre width of the narrow teeth
12--e.g. the centre width of the narrow teeth 12 could be about 0.3
mm or even smaller). In combination with the wide guard teeth 11
and the narrow teeth 12, the narrow tooth gaps 13 ensure that even
the flexible skin in the intimate area cannot penetrate through the
tooth gaps 13 and cutting of the skin is avoided, while a high
efficiency of the hair cutting performance of a hair trimmer device
employing such a trimmer comb is ensured.
[0037] In FIG. 2 it is also shown that the length E2 of the narrow
teeth 12 (the extension of the narrow teeth 12 from the basis at
the base sheet 10 to the tip measured in axial direction, which is
the x direction) is smaller than the length E1 of the guard teeth
11. The advantages of a reduced geometry obtained by narrow teeth
12 having a smaller overall width than the guard teeth 11 and by
retracted narrow teeth 12 are combined. As the definition of the
width of a trimmer comb tooth may be rather ambiguous for specific
tooth geometries, it is clearer to state that the base spacing D2'
of the narrow teeth 12 (the base spacing D2' being the
centre-to-centre distance between the tooth gap 13 on one side of a
narrow tooth 12 to the tooth gap 13 on the other side of the narrow
tooth 12) is smaller than the base spacing D2 of the guard tooth
11. It is the gist of the present invention to allow for good skin
protection while allowing for a high cutting efficiency. This is
achieved by a combination of those two factors, the reduction of
the spacing distance of the narrow teeth 12 and the retraction of
the narrow teeth 12.
[0038] In FIG. 3 a schematic frontal view onto the toothed front
side of an exemplary embodiment of a trimmer comb 1 (combining
different features of trimmer combs as proposed) and of an
associated trimmer blade 8 is shown. A Cartesian coordinate system
with axis y (longitudinal extension direction) and axis z (height
extension direction) is indicated. The trimmer blade 8 comprises a
base sheet 80 and a toothed front side having trimmer blade teeth
81. Even though the trimmer blade 8 is depicted with some distance
to the trimmer comb 1, the mounted trimmer blade 8 is contacting
the trimmer comb 1 at least at the toothed front side in a
tight-fit manner, usually under pre-stress, e.g. applied by a
spring (not shown). In a use operation, the trimmer blade 8 and the
trimmer comb 1 are moved relatively to each other in an oscillatory
manner, as indicated by double arrow R. The trimmer comb 1
comprises a base sheet 10 having guard teeth 11 and narrow teeth
12. In between the guard teeth 11 and the narrow teeth 12 teeth
gaps 13 are formed into which hairs feed in. In this schematic
frontal view, the guard teeth 11 have a cross sectional area C1
defined by the tips 15 of the guard teeth that is larger than the
cross sectional area C2 defined by the tips 15' of the narrow teeth
12. I
[0039] In the centre of the trimmer comb 1 as depicted in FIG. 3,
two guard teeth 11 are shown that have a thickened tip 11d, which
thickened tip 11d comprises a spherical tip portion that is formed
on the skin side S1 of the trimmer comb. Instead of only designing
guard teeth 11 with wide tips in longitudinal extension direction
y, the tips of the guard teeth 11 could also be thickened in height
direction z. The manufacturing and further details of such very
large thickened tips 11d will be discussed further below. On the
right hand side of FIG. 3 another embodiment of a thickened tip
11d' of a guard tooth 11 is schematically depicted. The tip 11d' is
only slightly thickened in z direction when compared to the tips
11d. Such thickened tips 11d' are known, e.g. from the Braun Lady
Shaver trimmer combs mentioned above.
[0040] In the following, a specific embodiment of a trimmer comb
for reduced risk for skin injuries and/or irritations and pleasing
skin contact sensation is discussed. This specific embodiment is
characterized by thickened tips (thickened in z direction, as
indicated in FIG. 3) of guard teeth. A specific process is
described to enable the manufacturing of extremely large thickened
tips in comparison to the base sheet thickness. As is described in
JP 02-052688, it is known to have hemispherical trimmer comb tips
for a gentle skin feeling, but this document describes a
manufacturing process of a trimmer comb involving sintering of
ceramic powder, which is a very costly process. Further, in
international patent application WO 2007/06177 A2 it is also
described to use thickened tooth tips to reduce the possibility of
hooking of the trimmer comb teeth into skin pores or hair channels,
but this document does not describe any manufacturing possibilities
of thickened tips. While the following embodiment is described with
respect to a plurality of guard teeth having thickened tips and a
plurality of narrow teeth that are arranged in an alternate manner,
it is to be understood that the described solution to the object of
providing a trimmer comb with improved skin contact sensation can
also be employed for trimmer combs having only guard teeth.
[0041] FIG. 4 shows a perspective view onto an intermediate trimmer
comb 100 in an intermediate manufacturing step after a base sheet
10 was punched and folded into the shown form. A detail of the
intermediate trimmer comb 100 is magnified for improved visibility
of details of the toothed front side. The base sheet 10 has an
elevated middle section 17 that has perforations 19 for placing the
final trimmer comb onto a carrier and for providing guiding slots
as is known in the art. The trimmer comb 100 has a toothed front
side of which a detail is magnified. The toothed front side
comprises intermediate guard teeth 11' and narrow teeth 12 arranged
side-by-side in an alternating manner. The intermediate guard teeth
11' have a bent over portion 11a. It is to be understood that the
step of forming a base sheet into an intermediate trimmer comb 100
(e.g. by punching or etching) and the step of bending over the
bent-over portions 11a of the intermediate guard teeth 11' could be
a single integrated step (e.g. a punching step in which the
protrusions 11a' of the intermediate guard teeth 11' are folded as
an effect of a preformed negative into which the base sheet 10 is
pressed during punching). In the folding part of the punching and
folding step, also other parts of the base sheet 10 could become
folded or elevated as, e.g., the elevated section 17 (it is
referred to FIG. 8, a side view of the intermediate trimmer comb,
in which the elevated section 17 is clearly depicted). In an
exemplary realization, the various steps of punching out the teeth
11, 12 and the perforations 19 (FIG. 6) and folding the elevated
section 17 into the base sheet and bending over the bent-over
portions 11a could are individual steps performed by a follow-on
composite tool. Instead of punching other known techniques could be
used to form the teeth, e.g. etching, wire erosion, laser cutting,
or water jet cutting.
[0042] FIG. 5 shows a top view onto the intermediate trimmer comb
100 as depicted in FIG. 4. Details about the intermediate guard
teeth 11' and the narrow teeth 12 are shown in and discussed with
reference to FIG. 6. In the shown embodiment, the narrow teeth 12
extend from their basis at the base sheet 10 until a line L1 and
the intermediate guard teeth 11' are bent over in such a manner
that they extend from their basis at the base sheet 10 until a line
that essentially will become a skin contact edge L2 of the final
trimmer comb (shown in FIG. 8). The intermediate trimmer comb 100
has two non-toothed side portions 18 concluding the toothed toothed
front side.
[0043] Instead of an intermediate trimmer comb 100 with a linear
skin contact edge L2, the intermediate trimmer comb 100 could also
have a curved skin contact edge L2. In other embodiments, two or a
multiplicity of narrow teeth 12 could be arranged between two
intermediate guard teeth 11'. While the subject matter of the
description covers also embodiments with one single tooth geometry
(only intermediate guard teeth 11' are arranged side by side), it
is to be noted that an alternate arrangement of intermediate guard
teeth 11' and narrow teeth 12 in combination with narrow tooth gaps
allows the manufacture of relatively large sized thickened tips
while ensuring a high cutting efficiency and optimized reduction of
the risk of skin injuries.
[0044] In FIG. 6, a detail A of the intermediate trimmer comb as
depicted in FIG. 5 is shown, but with the bent-over portions 11a,
which are shown in FIG. 5 in a bent over state, shown as
protrusions 11a' before bending for sake of clarity of the
depiction. Intermediate guard teeth 11' and narrow teeth 12 are
arranged side-by-side in an alternate manner. The narrow teeth 12
extend from their basis at the base sheet 10 until a line L1 and
the intermediate guard teeth 11' are bent over (as shown in FIGS. 4
and 5) at a line L2 that will essentially become the skin contact
edge of the final trimmer comb. The distance between the line L1
and the line L2 is about the thickness d of the base sheet material
(it is referred to FIG. 8, where the thickness d of the base sheet
material is indicated). The intermediate guard teeth 11' and the
narrow teeth 12 are tapered towards the line L1. The spacing
distance between a pair of a guard tooth 11 and a narrow tooth 12
is D1, so that the average spacing distance between the teeth of
the proposed comb is D.sub.avg=D1/2. The base spacing of an
intermediate guard tooth (and hence of a guard tooth 11 in its
final stage as discussed further below) measured between a base
centre of a tooth gap 13 on one side of an intermediate guard tooth
11' to the base centre of a tooth gap 13 on the other side of the
same intermediate guard tooth 11' is D2 and the base spacing of a
narrow tooth 12 measured between a base centre of a tooth gap 13 on
one side of a narrow tooth 12 to the base centre of a tooth gap 13
on the other side of the same narrow tooth 12 is D2', so that
D1=D2+D2'=2D.sub.avg. It is a specific feature of the discussed
embodiments that D2>D2', as the smaller base spacing D2' of the
narrow teeth 12 leads to the good cutting efficiency, while the
larger base spacing D2 of the guard teeth 11 allows to have wide
tips of the guard teeth 11 of the final trimmer comb. The centre
width of the guard teeth 11 is W.sub.c and the centre width of the
narrow teeth 12 is w.sub.c. In one embodiment, W.sub.c is about 0.5
mm and w.sub.c is about 0.3 mm. The centre width is measured at
half the axial extension of the narrow teeth for both, the narrow
teeth and the guard teeth. The intermediate guard teeth 11' have a
width W.sub.b at line L1 that is smaller than the centre width
W.sub.c of the guard teeth, W.sub.b<W.sub.c. The protrusion 11a'
of the intermediate guard teeth 11' first broadens to a middle
section of the bent-over portion 11a, where the bent-over portion
11a has a width W.sub.t, and than the protrusion 11a' tapers again.
As will be discussed in connection with FIG. 8, the protrusion 11a'
provides base sheet material for manufacturing a thickened tip much
thicker than the base sheet material by melting the bent-over
portion 11a and the broadened middle section of the protrusion 11a'
was found to improve the manufacturing process. Nevertheless, it is
to be understood that any other form of the protrusion 11a' is also
encompassed by the description. The centre width of a tooth gap 13
is D3, which in an exemplary embodiment is about 0.3 mm or less
(the centre width of the tooth gaps is also measured at half the
axial extension length of the narrow teeth). The centre-to-centre
distance between a narrow tooth 12 and an adjoining tooth gap 13 is
D4, which is in the shown embodiment equal to the centre width D3
of a tooth gap 13 or equal to the centre width w.sub.c of a narrow
tooth 12, hence, w.sub.c.apprxeq.D3.apprxeq.D4. Nevertheless, any
variation to these geometric parameters is also possible and may be
chosen according to the desired reduction in possible skin injuries
(via skin penetrating through the tooth gaps and getting cut) and
the desired cutting efficiency (the smaller the tooth gaps 13 are
in comparison with the narrow tooth 12, the lower the cutting
efficiency will become).
[0045] FIG. 7 shows a frontal view onto the toothed front side of
the intermediate trimmer comb 100. A detail of the frontal view is
magnified for improved visibility of details. The bent-over
portions 11a of the intermediate guard teeth can be seen as well as
the narrow teeth 12. The elevated section 17 of the base sheet is
also visible. As is known in the art, the elevated section 17 is
used for reduced friction between the final trimmer comb and the
trimmer blade (not shown).
[0046] In FIG. 8 a side view onto the intermediate trimmer comb 100
is shown. The elevated section 17 of the base sheet 10 is clearly
visible. The thickness d of the base sheet 10 is indicated. In the
shown embodiment, a base sheet thickness of d=0.3 mm is chosen to
ensure that hairs are cut as close to the skin as possible and to
allow for a low tooth spacing. In this side view also the
non-toothed side section 18 of the intermediate trimmer comb 100 is
depicted as well as the bent-over portion 11a of an intermediate
guard tooth. In FIG. 6 it is also indicated that a beam of energy
51 emitted from an energy source 50 is directed towards the
bent-over portion 11a of the intermediate guard tooth. Such a beam
of energy 51 could e.g. be a laser beam emitted from a laser
source. Using a laser beam, it is advisable to surround the
intermediate trimmer comb with a protective inert gas such as
argon. When applying energy to the energy to the bent-over portion
11a, the base sheet material (e.g. steel) provided by the bent-over
portion 11a melts and a solidified tip portion results, so that the
guard teeth 11 have extremely thickened tips as a result of the
manufacturing process (as will be discussed in connection with FIG.
9).
[0047] In FIG. 9, a side view onto a trimmer comb 1 in its final
stage is shown. The energy that was applied to the bent-over
portions 11a of the intermediate guard teeth 11' has molten most of
the base sheet material provided by the bent-over portions 11a and
a solidified tip portion 11b results when the material cools. Due
to the surface tension of the material in its molten state, an
essentially spherical thickening will usually result. By
fine-tuning the amount of energy applied to the bent-over portion
11a it can be achieved that a non-molten remainder 11c of the
bent-over portion 11a and of the guard tooth 11 remains, so that
the molten tip portion 11b is only formed on the skin side S1 of
the trimmer comb 1. Specifically, the blade side S2 of the trimmer
comb is not affected by the step of applying energy to the
bent-over portions 11a and the non-molten remainder 11c is left
over. The side S2 of the toothed front side may be grinded or
polished to assure optimal flatness and hence optimal contact with
the trimmer blade.
[0048] When mounted in a hair trimmer device, the trimmer comb 1
will contact the skin with its skin side S1. Hence, the smooth
solidified tip portions 11b will contact the skin and a pleasant
skin contact sensation results. As the process of manufacturing the
tip portions 11b allows spherical thickenings 11b that have a
diameter D that is much larger than the thickness d of the base
sheet 10 (in the shown embodiment, a diameter D of 0.7 mm is
achieved, which is more than twice the thickness d=0.3 mm of the
base sheet material), a thin base sheet 10 can be used while
thickened tips of the guard teeth 11 can be provided that are large
enough to effectively reduce any hooking of the guard tooth tips
into skin pores or hair channels. It is also to be noted that the
diameter D of the solidified tip portion (or the width measured in
longitudinal extension direction y) is in the discussed embodiment
slightly larger than the average spacing distance D.sub.avg between
the teeth of the proposed comb, where D=0.7 mm and D.sub.avg 1.35
mm/2. The proposed reduced geometry of the narrow teeth 12 obtained
by a combination of retracted narrow teeth 12 and of a small base
spacing D2' (as indicated in FIG. 6), where D2'=0.55 mm in
comparison to the base spacing D2=0.8 mm of the guard teeth 11 in
the exemplary embodiment, allows having thickened tip that are
wider (diameter D) in y direction than the average spacing distance
D.sub.avg. Various deviations to these geometric parameters of the
shown exemplary embodiment are of course possible and are
encompassed by the subject matter of the description.
[0049] FIG. 10 shows a perspective view onto the trimmer comb 1 in
its final stage.
[0050] FIG. 11 shows a magnification of the detail A' that is
indicated in FIG. 10. The magnification shows the solidified tip
portions 11b that had been formed at the tips of the guard teeth 11
by applying energy to the bent-over portions 11a so that the
material provided by the bent-over portions 11a was (mostly)
molten. By fine-tuning the amount of energy applied to the
bent-over portions 11a, it can be achieved that non-molten
remainders 11c of the bent-over portions 11a remain, so that the
molten tip portions 11b are only formed on that side of the trimmer
comb 1 to which the bent-over portions 11a were bent over (which
here is the skin side S1 as depicted in FIG. 9). The blade side S2,
as depicted in FIG. 9, would in this case not be affected by the
melting process and burrs and/or sharp edges are not formed at the
blade side even if the blade side is grinded and/or polished after
the step of applying energy to the bent-over portions 11a and
melting them. The guard teeth 11 of the trimmer comb 1 in its final
stage do not extend beyond the skin contact edge L2, as depicted in
FIG. 5, as in the step of applying energy to the bent-over portions
11a, the melting material topples over onto the guard teeth 11 or
sinks into the molten mass, specifically when the energy is applied
onto the side of the bent-over portions 11a that faces the base
sheet 10, as is depicted in FIG. 8. In the shown embodiment, the
narrow teeth 12 do extend until about the centre of the molten tip
portions 11b of the guard teeth 11. In this embodiment, hooking of
the tips of the narrow teeth 12 into skin pores or hair channels is
effectively avoided as the tips of the narrow teeth 12 cannot
contact the skin. Further, as the narrow teeth 12 do not extend to
the skin contact edge L2 (as depicted in FIG. 5), hairs can easily
feed into the teeth gaps 13. It is again noted that the guard teeth
11 have a centre width (W.sub.c in FIG. 6) that is wider that the
centre width (w.sub.c in FIG. 4) of the narrow teeth 12 and hence
allow for large solidified tip portions 11b that press the skin
down (while providing a pleasant skin contact sensation) and also
do not hook into skin pores or hair channels. The narrow teeth 12
arranged between the guard teeth 11 allow for high cutting
efficiency. The specific manufacturing process as described above
further allows for using a thin base sheet 10 (e.g. about 0.3 mm),
while solidified tip portions 11b can be formed that have a
diameter much larger than the base sheet thickness (in the
embodiment shown, the diameter of the spherical thickening is about
2.3 times as large as the base sheet thickness).
[0051] For sake of clarity it is noted that an intermediate guard
tooth 11' relates to the intermediate trimmer comb and comprises a
tooth portion that extends from the base sheet and either a
protrusion 11a' or a bent-over portion 11a, depending on the
manufacturing stage of the intermediate trimmer comb; the guard
tooth 11 relates to the trimmer comb in its final stage and
comprises a tooth portion that extends from the base sheet and a
solidified tip portion 11b and, optionally, a remainder 11c that
was not molten in the manufacturing process.
[0052] FIG. 12 shows an exemplary hair removal device 300 that
comprises a hair trimmer 200 in which a trimmer comb as described
can be used. In this exemplary hair removal device, a hair trimmer
device is combined with a wet shaver mounted on the back of the
hair removal device. Such a hair removal device is specifically
suitable for body grooming.
[0053] It is to be noted that any use of "include" or "comprise" in
the description or the claims shall mean "include, but not
necessarily limited to". Any use of "a" or "an" in the description
or the claims in combination with a feature shall not limit this
feature to be present only once but shall include also a multiple
presence of the feature.
[0054] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm".
[0055] All documents cited in the Detailed Description of the
invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention. To the
extend that any meaning or definition of a term in this written
document conflicts with any meaning or definition of the term in a
document incorporated by reference, the meaning or definition
assigned to the term in this written document shall govern.
[0056] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *